The Negotiator has no super human powers; however he is an extremely skilled negotiator and has access to the vast resources of the Reach. He has been able to employ extremely powerful Probes, Beetle Scarabs and ships capable of Inter Planetary travel.

Origins:

Negotiators appear to be the spoke persons of the Reach Empire. There full political powers have never truly been explained but they seem to enjoy full authority over Reach facilities on the planet they are assigned to. The Negotiator was assigned to Planet Earth within the Sol system when the dormant Reach Scarab was activated.